Organic light emitting display device

ABSTRACT

An organic light emitting display device is provided. The organic light emitting display device may include at least one light emitting part between an anode and a cathode, and the at least one light emitting part having at least one organic layer and a light emitting layer, wherein the at least one organic layer comprises a compound represented by Chemical Formula 1 or 2.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority benefit of Korean PatentApplication Nos. 10-2015-0171452 filed on Dec. 3, 2015, and10-2016-0057107 filed on May 10, 2016, which are all incorporated hereinby reference for all purposes as if fully set forth herein.

BACKGROUND OF THE DISCLOSURE

Field of the Disclosure

The present disclosure relates to an organic light emitting displaydevice, and more particularly, to an organic light emitting displaydevice with reduced operating voltage and improved efficiency.

Discussion of the Related Art

Image displays used for displaying a variety of information on thescreen are one of the core technologies of the information andcommunication era. Such image displays have been developed to bethinner, lighter, more portable, and to have high performance. With thedevelopment of the information society, various demands for displaydevices are on the rise. To meet these demands, research on paneldisplays such as liquid crystal displays (LCD), plasma display panels(PDP), electroluminescent displays (ELD), field emission displays (FED),organic light emitting diodes (OLED), etc. is actively under way.

Among these types of displays, the organic light emitting displaydevices are a type of devices that, when the charges are injected intoan organic emissive layer formed between an anode and a cathode, theemission of light due to the formation of electron-hole pairs takesplace and extinguishes. The organic light emitting display devices areadvantageous in that they can be fabricated on a flexible transparentsubstrate such as plastic substrate, can be operated at a relatively lowvoltage, have less power consumption, and deliver vivid colorreproduction, as compared with the plasma display panels or theinorganic light emitting displays. Particularly, the white OLED devicesare used for various purposes in lighting, thin light sources,backlights for liquid crystal displays, or full-color displays employingcolor filters.

An organic light emitting display device has a lamination structure ofan anode, a hole injection layer, a hole transport layer, an lightemitting layer, an electron transport layer, an electron injectionlayer, and a cathode, and the hole injection layer and the electroninjection layer are used to facilitate charge injection. A P-type holeinjection layer, which is a type of hole injection layer, is involved inthe generation, injection, and transport of holes. The P-type holeinjection layer is a layer formed of a single P-type material, orincludes a host and a P-type material therein. The host serves to injectholes from the anode into the light emitting layer through the HOMO(highest occupied molecular orbital) energy level, and is a materialcommonly used as the hole injection layer. The P-type dopant is amaterial that has a strong electron-attracting substituent and attractselectrons from the LUMO (lowest unoccupied molecular orbital) energylevel of the hole transport layer adjacent to the P-type hole injectionlayer to the HOMO energy level of the P-type dopant. The P-type holeinjection layer with a strong electron-attracting substituent forms ahole transport path by accepting electrons from the HOMO energy level ofthe host or the HOMO energy level of the hole injection layer or holetransport layer to the LUMO energy level of the P-type hole injectionlayer. After all, the LUMO energy level of the P-type hole injectionlayer and the HOMO energy level of the hole transport layer adjacent tothe P-type hole injection layer or the host may be similar in energylevel to enable efficient hole generation, so P-type hole injectingmaterials having a strong electron-attracting substituent are needed.

However, the P-type hole injecting materials are not easy to synthesizedue to their strong electron-attracting substituent, and have problemswith thermal stability and deposition stability. Particularly, F₄-TCNQ,one of the P-type hole injecting materials, sublimes easily, whichaffects the contamination of deposition sources, the performancereproducibility and thermal stability of devices during devicefabrication. Moreover, it is not easy to develop P-type hole injectingmaterials whose LUMO energy level is similar to the HOMO energy level ofthe host or the HOMO energy level of the hole transport layer. In orderto make the LUMO energy level similar to the HOMO energy level, it isnecessary to introduce a strong electron-attracting substituent into theP-type hole injecting material. However, the stronger theelectron-attracting substituent is, the harder it is to improve thepurity of the material, making the synthesis of the material difficult.Besides, it is necessary that the strong electron-attracting substituentdoes not absorb visible light, which makes the development of P-typehole injecting materials difficult.

SUMMARY OF THE DISCLOSURE

Accordingly, the present disclosure is directed to an organic lightemitting display device that substantially obviates one or more of theproblems due to limitations and disadvantages of the related art.

An object of the present disclosure is to provide an organic lightemitting display device with reduced operating voltage and improvedefficiency.

Additional features and advantages of the disclosure will be set forthin the description which follows, and in part will be apparent from thedescription, or may be learned by practice of the disclosure. Theobjectives and other advantages of the disclosure will be realized andattained by the structure particularly pointed out in the writtendescription and claims hereof as well as the appended drawings.

To achieve these and other advantages and in accordance with the purposeof the disclosure, as embodied and broadly described, an organic lightemitting display device comprises at least one light emitting partbetween an anode and a cathode, and the at least one light emitting parthaving at least one organic layer and a light emitting layer, whereinthe at least one organic layer comprises a compound represented by thefollowing Chemical Formula 1 or 2:

-   -   where R₁ to R₆ each independently represents one among a        hydrogen atom, a substituted or unsubstituted aryl group with 6        to 12 carbon atoms, a substituted or unsubstituted heteroaryl        group with 1 to 12 carbon atoms and 1 to 4 heteroatoms one among        O, N, S, and Si, a substituted or unsubstituted alkyl group with        1 to 12 carbon atoms, a substituted or unsubstituted alkoxy        group with 1 to 12 carbon atoms, a substituted or unsubstituted        ether group with 1 to 12 carbon atoms, a cyano group, a fluorine        group, a trifluoromethyl group, a trifluoromethoxy group, and a        trimethylsilyl group, and at least one among R₁ to R₆ comprises        a cyano group, and

Z₁ and Z₂ are independently represented by the following ChemicalFormula 3:

where A and B are independently represented by one among a hydrogenatom, a substituted or unsubstituted aryl group with 6 to 12 carbonatoms, a substituted or unsubstituted heteroaryl group with 1 to 12carbon atoms and 1 to 4 heteroatoms one among O, N, S, and Si, asubstituted or unsubstituted alkyl group with 1 to 12 carbon atoms, asubstituted or unsubstituted alkoxy group with 1 to 12 carbon atoms, asubstituted or unsubstituted ether group with 1 to 12 carbon atoms, acyano group, a fluorine group, a trifluoromethyl group, atrifluoromethoxy group, and a trimethylsilyl group.

The substituent of the aryl group, heteroaryl group, alkyl group, alkoxygroup, and ether group is one among an alkyl with 1 to 12 carbon atoms,an aryl with 6 to 15 carbon atoms, a hetero alkyl with 1 to 15 carbonatoms and 1 to 4 heteroatoms one among O, N, S, and Si, a cyano group, afluorine group, a trifluoromethyl group, a trifluoromethoxy group, and atrimethylsilyl group.

The compound represented by Chemical Formula 1 is represented by oneamong the following compounds:

The compound represented by the above Chemical Formula 2 is representedby one among the following compounds:

The at least one organic layer includes a hole injection layer.

A dopant of the hole injection layer includes the compound.

The hole injection layer includes the compound.

The at least one organic layer includes a P-type charge generationlayer.

A dopant of the P-type charge generation layer includes the compound.

The P-type charge generation layer includes the compound.

In another aspect, an organic light emitting display device comprises atleast one light emitting part between an anode and a cathode, and the atleast one light emitting part having a hole injection layer and a lightemitting layer, and a charge generation layer having a P-type chargegeneration layer between the at least one light emitting parts, whereinat least one among the hole injection layer and the P-type chargegeneration layer comprises a compound represented by the followingChemical Formula 1 or 2:

where R₁ to R₆ each independently represents one among a hydrogen atom,a substituted or unsubstituted aryl group with 6 to 12 carbon atoms, asubstituted or unsubstituted heteroaryl group with 1 to 12 carbon atomsand 1 to 4 heteroatoms one among O, N, S, and Si, a substituted orunsubstituted alkyl group with 1 to 12 carbon atoms, a substituted orunsubstituted alkoxy group with 1 to 12 carbon atoms, a substituted orunsubstituted ether group with 1 to 12 carbon atoms, a cyano group, afluorine group, a trifluoromethyl group, a trifluoromethoxy group, and atrimethylsilyl group, and at least one among R₁ to R₆ comprises a cyanogroup, and

Z₁ and Z₂ are independently represented by the following ChemicalFormula 3:

where A and B independently represent one among a hydrogen atom, asubstituted or unsubstituted aryl group with 6 to 12 carbon atoms, asubstituted or unsubstituted heteroaryl group with 1 to 12 carbon atoms,a substituted or unsubstituted alkyl group with 1 to 12 carbon atoms and1 to 4 heteroatoms one among O, N, S, and Si, a substituted orunsubstituted alkoxy group with 1 to 12 carbon atoms, a substituted orunsubstituted ether group with 1 to 12 carbon atoms, a cyano group, afluorine group, a trifluoromethyl group, a trifluoromethoxy group, and atrimethylsilyl group.

The substituent of the aryl group, heteroaryl group, alkyl group, alkoxygroup, and ether group is one among an alkyl with 1 to 12 carbon atoms,an aryl with 6 to 15 carbon atoms, a hetero alkyl with 1 to 15 carbonatoms and 1 to 4 heteroatoms one among O, N, S, and Si, a cyano group, afluorine group, a trifluoromethyl group, a trifluoromethoxy group, and atrimethylsilyl group.

The compound represented by Chemical Formula 1 is represented by oneamong the following compounds:

The compound represented by the above Chemical Formula 2 is representedby one among the following compounds:

A dopant for the hole injection layer includes the compound.

The hole injection layer includes the compound.

A dopant for the P-type charge generation layer includes the compound.

The P-type charge generation layer includes the compound.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the disclosure and are incorporated in and constitute apart of this specification, illustrate embodiments of the disclosure andtogether with the description serve to explain the principles of thedisclosure.

FIG. 1 is a cross-sectional view showing an organic light emittingdisplay device according to a first exemplary embodiment of the presentdisclosure.

FIG. 2 is a cross-sectional view showing an organic light emittingdisplay device according to a second exemplary embodiment of the presentdisclosure.

FIG. 3 is a cross-sectional view showing an organic light emittingdisplay device according to a third exemplary embodiment of the presentdisclosure.

FIGS. 4 and 5 are energy band diagrams of an organic light emittingdisplay device according to one or more embodiments of the presentdisclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The advantages and features of the present disclosure and methods foraccomplishing the same may be understood more readily by reference tothe following detailed descriptions of exemplary embodiments and theaccompanying drawings. The present disclosure may, however, be embodiedin many different forms and should not be construed as being limited tothe exemplary embodiments set forth herein. Rather, these exemplaryembodiments are provided so that this disclosure will be thorough andcomplete and will fully convey the concept of the present disclosure tothose skilled in the art, and the present disclosure is defined by theappended claims.

The shapes, sizes, percentages, angles, numbers, etc shown in thefigures to describe the exemplary embodiments of the present disclosureare merely examples and not limited to those shown in the figures. Likereference numerals denote like elements throughout the specification. Indescribing the present disclosure, detailed descriptions of relatedwell-known technologies will be omitted to avoid unnecessary obscuringthe present disclosure. When the terms ‘comprise’, ‘have’, ‘consist of’and the like are used, other parts may be added as long as the term‘only’ is not used. The singular forms may be interpreted as the pluralforms unless explicitly stated.

The elements may be interpreted to include an error margin even if notexplicitly stated.

When the position relation between two parts is described using theterms ‘on’, ‘over’, ‘under’, ‘next to’ and the like, one or more partsmay be positioned between the two parts as long as the term‘immediately’ or ‘directly’ is not used.

When the temporal relationship between two events is described using theterms ‘after’, ‘following’, ‘next’, ‘before’ and the like, the twoevents may not occur in succession as long as the term ‘immediately’ or‘directly’ is not used.

It will be understood that, although the terms first, second, etc., maybe used to describe various elements, these elements should not belimited by these terms. These terms are only used to distinguish oneelement from another element. Thus, a first element discussed belowcould be termed a second element without departing from the technicalspirit of the present disclosure.

The features of various exemplary embodiments of the present disclosuremay be combined with one another either partly or wholly, and maytechnically interact or work together in various ways. The exemplaryembodiments may be carried out independently or in combination with oneanother.

Hereinafter, various exemplary embodiments of the present disclosurewill be described in detail with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view showing an organic light emittingdisplay device according to a first exemplary embodiment of the presentdisclosure. All the components of the organic light emitting displaydevice according to all embodiments of the present disclosure areoperatively coupled and configured.

Referring to FIG. 1, an organic light emitting display device 100according to the first exemplary embodiment of the present disclosurecomprises an anode 110, a hole injection layer 120, a hole transportlayer 130, an light emitting layer 140, an electron transport layer 150,an electron injection layer 210, and a cathode 220.

The anode 110 is a hole injection electrode, and may be formed of oneamong ITO (indium tin oxide), IZO (indium zinc oxide), or ZnO (zincoxide) having a high work function. Also, if the anode 110 is areflective electrode, the anode 110 may further comprise a reflectivelayer formed of one among aluminum (Al), silver (Ag), or nickel (Ni)under a layer formed of one among ITO, IZO, or ZnO.

The hole injection layer 120 is formed on the anode 110. The holeinjection layer 120 has to comprise a strong electron-attractingsubstituent, in order to make LUMO energy level of the hole injectionlayer similar to or lower than the HOMO energy level of the host of thehole injection layer or the HOMO energy level of the hole transportlayer. However, compounds comprising an electron-attracting substituentare hard to synthesize because of the electron-attracting substituents,and are not easy to develop due to their low thermal and depositionstability. In view of this, the present inventors conducted varioustests to improve the hole injection properties and the device'sefficiency and lifetime by forming a hole injection layer of a materialthat ensures process stability and comprises an electron-attractingsubstituent.

Through a number of tests or experiments which were performed onmaterials that do not affect the lifetime or efficiency of the organiclight emitting display device and that cause no rise in operatingvoltage, the present inventors developed compounds that can exhibit holeinjection properties by ensuring process stability and comprising anelectron-attracting substituent. In the present disclosure, a holeinjection layer is formed using a compound comprising indene as a coreand an electron-attracting substituent. The composition and depositionof the compound is simplified because indene provides process stabilityagainst heat or deposition. Moreover, the compound of this disclosurecan improve the hole injection properties by comprising anelectron-attracting substituent attached to the core and making the LUMOenergy level of the compound similar to or lower than the HOMO energylevel of the host of the hole injection layer 120, the host of a P-typecharge generation layer, or the hole transport layer.

Accordingly, the hole injection layer 120 of this disclosure comprises acompound represented by the following Chemical Formula 1 or 2:

where R₁ to R₆ each independently represents one among a hydrogen atom,a substituted or unsubstituted aryl group with 6 to 12 carbon atoms, asubstituted or unsubstituted heteroaryl group with 1 to 12 carbon atomsand 1 to 4 heteroatoms one among O, N, S, and Si, a substituted orunsubstituted alkyl group with 1 to 12 carbon atoms, a substituted orunsubstituted alkoxy group with 1 to 12 carbon atoms, a substituted orunsubstituted ether group with 1 to 12 carbon atoms, a cyano group, afluorine group, a trifluoromethyl group, a trifluoromethoxy group, and atrimethylsilyl group, and at least one among R₁ to R₆ comprises a cyanogroup.

Z₁ and Z₂ are independently represented by the following ChemicalFormula 3:

where A and B are independently represented by one among a hydrogenatom, a substituted or unsubstituted aryl group with 6 to 12 carbonatoms, a substituted or unsubstituted heteroaryl group with 1 to 12carbon atoms, a substituted or unsubstituted alkyl group with 1 to 12carbon atoms and 1 to 4 heteroatoms one among O, N, S, and Si, asubstituted or unsubstituted alkoxy group with 1 to 12 carbon atoms, asubstituted or unsubstituted ether group with 1 to 12 carbon atoms, acyano group, a fluorine group, a trifluoromethyl group, atrifluoromethoxy group, and a trimethylsilyl group.

The substituent of the aryl group, heteroaryl group, alkyl group, alkoxygroup, and ether group may be one among an alkyl with 1 to 12 carbonatoms, an aryl with 6 to 15 carbon atoms, a hetero alkyl with 1 to 15carbon atoms and 1 to 4 heteroatoms one among O, N, S, and Si, a cyanogroup, a fluorine group, a trifluoromethyl group, a trifluoromethoxygroup, and a trimethylsilyl group.

The compound represented by Chemical Formula 1 is represented by atleast one among the following compounds:

The compound represented by the above Chemical Formula 2 is representedby one among the following compounds:

The above-described compound of this disclosure comprises indene as acore, which provides process stability against heat or deposition, thussimplifying the composition and deposition of the compound. Moreover,the compound of this disclosure improves the hole injection propertiesby comprising an electron-attracting substituent attached to the coreand making the LUMO energy level of the compound similar to or lowerthan the HOMO energy level of the host of the hole injection layer, thehost of the P-type charge generation layer, or the hole transport layer.

Accordingly, the hole injection layer is formed of the compound of thisdisclosure to ensure the process stability of the compound, simplifyingthe fabrication of the organic light emitting display device. Moreover,the compound of this disclosure can reduce the device's operatingvoltage and improve its efficiency and lifetime since the improvement inhole injection properties helps to facilitate the transfer of holes fromthe anode to the light emitting layer.

The hole injection layer 120 may be formed of a compound of thisdisclosure, or may comprise the compound as a dopant. The hole injectionlayer 120 may form solely of a compound of this disclosure. Also, if thehole injection layer 120 comprises a compound of this disclosure as adopant, the hole injection layer 120 may comprise one or more hostsamong CuPc(copper phthalocyanine),PEDOT(poly(3,4)-ethylenedioxythiophene), PANI(polyaniline),DNTPD(N1′,N1″-(biphenyl-4,4′-diyl)bis(N¹-phenyl-N⁴,N⁴-di-m-tolylbenzene-1,4-diamine),andNPD(N,N′-bis(naphthalene-1-yl)-N,N′-bis(phenyl)-2,2′-dimethylbenzidine)and a dopant comprising the compound of this disclosure.

The hole injection layer 120 may have a 1 to 150 nm thickness. If thehole injection layer 120 has a 1 nm thickness or greater, the holeinjection properties may be improved. If the hole injection layer 120has a 150 nm thickness or less, an increase in the thickness of the holeinjection layer 120 may be prevented and a rise in operating voltage maybe therefore prevented.

The hole transport layer 130 may function to facilitate hole transport,and may be formed of, but is not limited to, one or more amongNPD(N,N′-bis(naphthalene-1-yl)-N,N′-bis(phenyl)-2,2′-dimethylbenzidine),TPD(N,N′-bis-(3-methylphenyl)-N,N′-bis(phenyl)-benzidine),spiro-TAD(2,2′7,7′-tetrakis(N,N-diphenylamino)-9,9′-spirofluorene),NPB(N,N′-bis(naphthalene-1-yl-N,N′-bis(phenyl)-benzidine), andMTDATA(4,4′,4″-Tris(N-3-methylphenyl-N-phenylamino)-triphenylamine). Thehole transport layer 130 may have a 1 to 150 nm thickness. If the holetransport layer 130 has a 1 nm thickness or greater, the hole transportproperties may be improved, or if the hole transport layer 130 has a 150nm thickness or less, an increase in the thickness of the hole transportlayer 130 may be prevented, and a rise in operating voltage may betherefore prevented. Moreover, an electron blocking layer may be furtherformed over the hole transport layer 130.

The light emitting layer 140 may emit light of red (R), green (G), orblue (B), and may be formed of a fluorescent material or phosphorescentmaterial.

If the light emitting layer 140 is a red light emitting layer, it may beformed of, but is not limited to, a fluorescent material comprisingPBD:Eu(DBM)₃(Phen) or perylene. If the light emitting layer 140 is agreen light emitting layer, it may be formed of, but is not limited to,a fluorescent material comprisingAlq₃(tris(8-hydroxyquinolinato)aluminum). If the light emitting layer140 is a blue light emitting layer, it may be formed of, but is notlimited to, a fluorescent material comprising one amongspiro-BDAVBi(2,7-bis[4-(diphenylamino)styryl]-9,9-spirofluorene),spiro-CBP(2,2′,7,7′-tetrakis(carbozol-9-yl)-9,9-spirofluorene),distyrylbenzene (DSB), distyrylarylene (DSA), a PFO (polyfluorene)polymer, and a PPV(polyphenylenevinylene) polymer.

The electron transport layer 150 may function to facilitate thetransport of electrons, and may be formed of, but is not limited to, oneor more among Alq₃(tris(8-hydroxyquinolinato)aluminum),PBD(2-4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole),TAZ(3-(4-biphenyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole),DPT(2-biphenyl-4-yl-4,6-bis-(4′-pyridin-2-yl-biphenyl-4-yl)-[1,3,5]triazine),and BAlq(Bis(2-methyl-8-quinolinolato)-4-(phenylphenolato)aluminum). Theelectron transport layer 150 may have a 1 to 150 nm thickness. If theelectron transport layer 150 has a 1 nm thickness or greater, adegradation of the electron transport properties may be prevented. Ifthe electron transport layer 150 has a 150 nm thickness or less, anincrease in the thickness of the electron transport layer 150 may beprevented, and a rise in operating voltage may be therefore prevented.

The electron injection layer 210 functions to facilitate electroninjection, and may be formed of, but is not limited to, one amongAlq₃(tris(8-hydroxyquinolinato)aluminum),PBD(2-4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole),TAZ(3-(4-biphenyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole), andBAlq(Bis(2-methyl-8-quinolinolato)-4-(phenylphenolato)aluminum). On theother hand, the electron injection layer 210 may be formed of a metalcompound, and the metal compound may be, for example, but is not limitedto, one or more among LiQ, LiF, NaF, KF, RbF, CsF, FrF, BeF₂, MgF₂,CaF₂, SrF₂, BaF₂, and RaF₂. The electron injection layer 210 may have a1 to 50 nm thickness. If the electron injection layer 210 has a 1 nmthickness or greater, a degradation of the electron injection propertiesmay be prevented. If the electron injection layer 210 has a 50 nmthickness or less, an increase in the thickness of the electroninjection layer 210 may be prevented, and a rise in operating voltagemay be therefore prevented. The electron injection layer 210 may not beincluded in the elements of the organic light emitting display device,depending on the structure or characteristics of the device.

The cathode 220 is an electron injection electrode, and may be formed ofmagnesium (Mg), calcium (Ca), aluminum (Al), silver (Ag), or an alloythereof, having a low work function. If the organic light emittingdisplay device is a top-emission type or a dual-emission type, thecathode 220 may be formed thin enough to pass light therethrough. If theorganic light emitting display device is a bottom-emission type, thecathode 220 may be formed thick enough to reflect light.

As above, a compound of this disclosure comprises indene as a core,which provides process stability against heat or deposition, thussimplifying the composition and deposition of the compound. Moreover,the compound of this disclosure improves the hole injection propertiesby comprising an electron-attracting substituent attached to the coreand making the LUMO energy level of the compound similar to or lowerthan the HOMO energy level of the host of the hole injection layer, thehost of the P-type charge generation layer, or the hole transport layer.

Accordingly, the hole injection layer is formed of the compound of thisdisclosure to ensure the process stability of the compound, whichsimplifies the fabrication of the organic light emitting display device.Moreover, the compound of this disclosure can reduce the device'soperating voltage and improve its efficiency and lifetime since theimprovement in hole injection properties helps to facilitate thetransfer of holes from the anode to the light emitting layer.

FIG. 2 is a view showing an organic light emitting display deviceaccording to a second exemplary embodiment of the present disclosure.The same elements as the first exemplary embodiment are denoted by thesame reference numerals, so descriptions of these elements will beomitted or may be brief below.

Referring to FIG. 2, an organic light emitting display device 100 of thepresent disclosure comprises light emitting parts ST1 and ST2 between ananode 110 and a cathode 220, and a charge generation layer 160 betweenthe light emitting parts ST1 and ST2.

The first light emitting part ST1 comprises a first light emitting layer140. The first light emitting layer 140 may emit light of red (R), green(G), or blue (B), and may be formed of a fluorescent or phosphorescentmaterial. In this exemplary embodiment, the first light emitting layer140 may be a blue light emitting layer. The blue light emitting layercomprises one among a blue light emitting layer, a dark blue lightemitting layer, and a sky blue light emitting layer. Alternatively, thefirst light emitting layer 140 may form of a blue light emitting layerand a red light emitting layer, a blue light emitting layer and ayellow-green light emitting layer, or a blue light emitting layer and agreen light emitting layer. If the first light emitting layer 140 is ablue light emitting layer, it may emit light over a wavelength range of440 to 480 nm. If the first light emitting layer 140 forms of a bluelight emitting layer and a red light emitting layer, it may emit lightover a wavelength range of 440 to 650 nm. If the first light emittinglayer 140 forms of a blue light emitting layer and a yellow-green lightemitting layer, it may emit light over a wavelength range of 440 to 590nm. If the first light emitting layer 140 forms of a blue light emittinglayer and a green light emitting layer, it may emit light over awavelength range of 440 to 580 nm.

The first light emitting part ST1 comprises a hole injection layer 120and a first hole transport layer 130 that are between the anode 110 andthe first light emitting layer 140, and a first electron transport layer150 on the first light emitting layer 140. Accordingly, the first lightemitting part ST1 comprising the hole injection layer 120, first holetransport layer 130, first light emitting layer 140, and first electrontransport layer 150 is formed on the anode 110. The first hole transportlayer 130 may be formed of, but is not limited to, the same material asthe hole transport layer 130 explained with reference to FIG. 1.

A charge generation layer (CGL) 160 is between the first light emittingpart ST1 and the second light emitting part ST2. The first lightemitting part ST1 and the second light emitting part ST2 are connectedby the charge generation layer 160. The charge generation layer 160 maybe a PN-junction charge generation layer formed by joining an N-typecharge generation layer 160N and a P-type charge generation layer 160P.The PN junction charge generation layer 160 generates a charge, orinjects the charge (i.e., electrons and holes), separately into thelight emitting layer. That is, the N-type charge generation layer 160Ntransfers electrons to the first electron transport layer 150, and thefirst electron transport layer 150 supplies the electrons to the firstlight emitting layer 140 adjacent to the anode, and the P-type chargegeneration layer 160P transfers holes to the second hole transport layer180, and the second hole transport layer 180 supplies the holes to thesecond light emitting layer 190 of the second light emitting part ST2.As such, the luminous efficiency of the first and second light emittinglayers 140 and 190 may be further increased, and the operating voltagemay be reduced.

The N-type charge generation layer 160N may be formed of a metal or anN-doped organic material. The metal may be one among Li, Na, K, Rb, Cs,Mg, Ca, Sr, Ba, La, Ce, Sm, Eu, Tb, Dy, and Yb. An N-type dopant andhost for the N-doped organic material may be commonly-used materials.For example, the N-type dopant may be an alkali metal, an alkali metalcompound, an alkali earth metal, or an alkali earth metal compound.Specifically, the N-type dopant may be one among Li, Cs, K, Rb, Mg, Na,Ca, Sr, Eu, and Yb. The host material may be an organic matter that hasa nitrogen atom-containing hetero ring, with 20 to 60 carbon atoms, forexample, one material among Alq₃(tris(8-hydroxyquinolinato)aluminum),triazine, a hydroxyquinoline derivative, a benzazole derivative, and asilole derivative.

The P-type charge generation layer 160P may be formed of the samematerial as the hole injection layer 120 of the above-described firstexemplary embodiment. A compound of this disclosure comprises indene asa core, which provides process stability against heat or deposition,thus simplifying the composition and deposition of the compound.Moreover, the compound of this disclosure improves the hole injectionproperties by comprising an electron-attracting substituent attached tothe core and making the LUMO energy level of the compound similar to orlower than the HOMO energy level of the hole transport layer.

Accordingly, the P-type charge generation layer is formed of thecompound of this disclosure to ensure the process stability of thecompound, which simplifies the fabrication of the organic light emittingdisplay device. Moreover, the compound of this disclosure can reduce thedevice's operating voltage and improve its efficiency and lifetime sincethe improvement in hole injection properties helps to facilitate thetransfer of holes from the anode to the light emitting layer.

The second light emitting part ST2 comprising a second hole transportlayer 180, the second light emitting layer 190, a second electrontransport layer 200, and an electron injection layer 210 is on thecharge generation layer 160.

The second light emitting layer 190 may emit light of red (R), green(G), blue (B), or yellow-green (YG), and may be formed of a fluorescentor phosphorescent material. In this exemplary embodiment, the secondlight emitting layer 190 may be a light emitting layer that emitsyellow-green light. The second light emitting layer 190 may have asingle layer structure of a yellow-green light emitting layer or a greenlight emitting layer, or a multilayer structure formed of a yellow-greenlight emitting layer and a green light emitting layer. The second lightemitting layer 190 comprises a yellow-green light emitting layer, agreen light emitting layer, or a multilayer structure formed of ayellow-green light emitting layer and a green light emitting layer, ayellow light emitting layer and a red light emitting layer, a greenlight emitting layer and a red light emitting layer, or a yellow-greenlight emitting layer and a red light emitting layer. If the second lightemitting layer 190 forms of a yellow-green light emitting layer, a greenlight emitting layer, or a yellow-green light emitting layer and a greenlight emitting layer, it may emit light over a wavelength range of 510to 590 nm. If the second light emitting layer 190 is formed of a yellowlight emitting layer and a red light emitting layer, a green lightemitting layer and a red light emitting layer, or a yellow-green lightemitting layer and a red light emitting layer, it may emit light over awavelength range of 510 to 650 nm.

This exemplary embodiment will be described by taking as an example asingle layer structure of a second light emitting layer 190 that emitsyellow-green light. The second light emitting layer 190 may comprise,but is not limited to, at least one host of CBP(4,4′-bis(carbazol-9-yl)biphenyl) andBAlq(Bis(2-methyl-8-quinolinolato)-4-(phenylphenolato)aluminum) and aphosphorescent yellow-green dopant that emits yellow-green light.

The second light emitting part ST2 comprises the second hole transportlayer 180 between the charge generation layer 160 and the second lightemitting layer 190, and comprises the second electron transport layer200 and electron injection layer 210 on the second light emitting layer190. The second hole transport layer 180 may be formed of, but is notlimited to, the same material as the hole transport layer 130 explainedwith reference to FIG. 1.

Accordingly, the second light emitting part ST2 comprising the secondhole transport layer 180, second light emitting layer 190, secondelectron transport layer 200, and electron injection layer 210 is formedon the charge generation layer 160. The cathode 220 is provided on thesecond light emitting part ST2 to constitute the organic light emittingdisplay device according to the second exemplary embodiment of thepresent disclosure.

The above-described second exemplary embodiment of the presentdisclosure has disclosed that the P-type charge generation layer 160Pcomprise a compound of this disclosure. As in the above-described firstexemplary embodiment, the compound of this disclosure may be also usedas the hole injection layer 120. The compound of this disclosure may beincluded in at least one among the hole injection layer 120 and theP-type charge generation layer 160P.

As above, a compound of this disclosure comprises indene as a core,which provides process stability against heat or deposition, thussimplifying the composition and deposition of the compound. Moreover,the compound of this disclosure improves the hole injection propertiesby comprising an electron-attracting substituent attached to the coreand making the LUMO energy level of the compound similar to or lowerthan the HOMO energy level of host of the hole injection layer, the hostof the P-type charge generation layer, or the hole transport layer.

Accordingly, at least one among the hole injection layer and the P-typecharge generation layer is formed of the compound of this disclosure toensure the process stability of the compound, which simplifies thefabrication of the organic light emitting display device. Moreover, thecompound of this disclosure can reduce the device's operating voltageand improve its efficiency and lifetime since the improvement in holeinjection properties helps to facilitate the transfer of holes from theanode to the light emitting layer.

FIG. 3 is a view showing an organic light emitting display deviceaccording to a third exemplary embodiment of the present disclosure. Thesame elements as the first and second exemplary embodiments are denotedby the same reference numerals, so descriptions of these elements willbe omitted or may be brief below.

Referring to FIG. 3, an organic light emitting display device 100 of thepresent disclosure comprises a plurality of light emitting parts ST1,ST2, and ST3 between an anode 110 and a cathode 220, and a first chargegeneration layer 160 and a second charge generation layer 230 that arebetween the light emitting parts ST1, ST2, and ST3. Although thisexemplary embodiment has been illustrated and described with an examplewhere three light emitting parts are between the anode 110 and thecathode 220, the present disclosure is not limited to this example andfour or more light emitting parts may be between the anode 110 and thecathode 220.

Among the light emitting parts, the first light emitting part ST1comprises a first light emitting layer 140. The first light emittinglayer 140 may emit light one among red, green, and blue. For example, itmay be a blue light emitting layer in this exemplary embodiment. Theblue light emitting layer comprises one among a blue light emittinglayer, a dark blue light emitting layer, and a sky blue light emittinglayer. Alternatively, the first light emitting layer 140 may form of ablue light emitting layer and a red light emitting layer, a blue lightemitting layer and a yellow-green light emitting layer, or a blue lightemitting layer and a green light emitting layer. If the first lightemitting layer 140 is a blue light emitting layer, it may emit lightover a wavelength range of 440 to 480 nm. If the first light emittinglayer 140 forms of a blue light emitting layer and a red light emittinglayer, it may emit light over a wavelength range of 440 to 650 nm. Ifthe first light emitting layer 140 forms of a blue light emitting layerand a yellow-green light emitting layer, it may emit light over awavelength range of 440 to 590 nm. If the first light emitting layer 140forms of a blue light emitting layer and a green light emitting layer,it may emit light over a wavelength range of 440 to 580 nm.

The first light emitting part ST1 comprises a hole injection layer 120and a first hole transport layer 130 that are between the anode 110 andthe first light emitting layer 140, and a first electron transport layer150 on the first light emitting layer 140. Accordingly, the first lightemitting part ST1 comprising the hole injection layer 120, the firsthole transport layer 130, the first light emitting layer 140, and thefirst electron transport layer 150 is formed on the anode 110.

The second light emitting part ST2 comprising a second light emittinglayer 190 is on the first light emitting part ST1. The second lightemitting layer 190 may emit light of one among red, green, blue, andyellow-green. For example, it may be a yellow-green light emitting layerin this exemplary embodiment. The second light emitting layer 190comprises a yellow-green light emitting layer, a green light emittinglayer, or a multilayer structure formed of a yellow-green light emittinglayer and a green light emitting layer, a yellow light emitting layerand a red light emitting layer, a green light emitting layer and a redlight emitting layer, or a yellow-green light emitting layer and a redlight emitting layer. If the second light emitting layer 190 forms of ayellow-green light emitting layer, a green light emitting layer, or ayellow-green light emitting layer and a green light emitting layer, itmay emit light over a wavelength range of 510 to 590 nm. If the secondlight emitting layer 190 forms of a yellow light emitting layer and ared light emitting layer, a green light emitting layer and a red lightemitting layer, or a yellow-green light emitting layer and a red lightemitting layer, it may emit light over a wavelength range of 510 to 650nm.

The second light emitting part ST2 further comprises a second holetransport layer 180 on the first light emitting part ST1, and comprisesa second electron transport layer 200 on the second light emitting layer190. Accordingly, the second light emitting part ST2 comprising thesecond hole transport layer 180, the second light emitting layer 190,and the second electron transport layer 200 is formed on the first lightemitting part ST1.

A first charge generation layer 160 is between the first light emittingpart ST1 and the second light emitting part ST2. The first chargegeneration layer 160 is a PN-junction charge generation layer formed byjoining an N-type charge generation layer 160N and a P-type chargegeneration layer 160P. The first charge generation layer 160 generates acharge, or injects the charge, i.e., electrons and holes, separatelyinto the first and second light emitting layers 140 and 190.

The third light emitting part ST3 comprising a third light emittinglayer 250 is on the second light emitting part ST2. The third lightemitting layer 250 may emit light one among red, green, and blue, and beformed of a fluorescent material. For example, it may be a blue lightemitting layer in this exemplary embodiment. The blue light emittinglayer comprises one among a blue light emitting layer, a dark blue lightemitting layer, and a sky blue light emitting layer. Alternatively, thethird light emitting layer 250 may form of a blue light emitting layerand a red light emitting layer, a blue light emitting layer and ayellow-green light emitting layer, or a blue light emitting layer and agreen light emitting layer. If the third light emitting layer 250 is ablue light emitting layer, it may emit light over a wavelength range of440 to 480 nm. If the third light emitting layer 250 forms of a bluelight emitting layer and a red light emitting layer, it may emit lightover a wavelength range of 440 to 650 nm. If the third light emittinglayer 250 forms of a blue light emitting layer and a yellow-green lightemitting layer, it may emit light over a wavelength range of 440 to 590nm. If the third light emitting layer 250 forms of a blue light emittinglayer and a green light emitting layer, it may emit light over awavelength range of 440 to 580 nm.

The third light emitting part ST3 further comprises a third holetransport layer 240 on the second light emitting part ST2, and a thirdelectron transport layer 260 and an electron injection layer 210 thatare on the third light emitting layer 250. Accordingly, the third lightemitting part ST3 comprising the third hole transport layer 240, thirdlight emitting layer 250, third electron transport layer 260, andelectron injection layer 210 is formed on the second light emitting partST2. The electron injection layer 210 may not be included in theelements of the third light emitting part ST3, depending on thestructure or characteristics of the device.

The second charge generation layer 230 is between the second lightemitting part ST2 and the third light emitting part ST3. The secondcharge generation layer 230 is a PN junction charge generation layerformed by joining the N-type charge generation layer 230N and the P-typecharge generation layer 230P. The second charge generation layer 230generates a charge, or injects the charge (i.e., electrons and holes),separately into the second and third light emitting layers 190 and 250.The cathode 220 is provided on the third light emitting part ST3 toconstitute the organic light emitting display device according to thethird exemplary embodiment of the present disclosure.

At least one among the hole injection layer 120, the P-type chargegeneration layer 160P of the first charge generation layer 160, and theP-type charge generation layer 260P of the second charge generationlayer 260 is formed of a compound of this disclosure, as in the case ofthe foregoing exemplary embodiments. A compound of this disclosurecomprises indene as a core, which provides process stability againstheat or deposition, thus simplifying the composition and deposition ofthe compound. Moreover, the compound of this disclosure improves thehole injection properties by comprising an electron-attractingsubstituent attached to the core and making the LUMO energy level of thecompound similar to or lower than the HOMO energy level of host of thehole injection layer, the host of the P-type charge generation layer, orthe hole transport layer.

Accordingly, at least one among the hole injection layer and the P-typecharge generation layer is formed of the compound of this disclosure toensure the process stability of the compound, which simplifies thefabrication of the organic light emitting display device. Moreover, thecompound of this disclosure can reduce the device's operating voltageand improve its efficiency and lifetime since the improvement in holeinjection properties helps to facilitate the transfer of holes from theanode to the light emitting layer.

Organic light emitting displays using the organic light emitting displaydevice according to the first to third exemplary embodiments of thepresent disclosure may include top emission displays, bottom emissiondisplays, dual emission displays, and vehicle lighting. The vehiclelighting may include, but are not necessarily limited to, headlights,high beams, taillights, brake lights, and back-up lights. Moreover,organic light emitting displays using the organic light emitting displaydevices according to the first to third exemplary embodiments of thepresent disclosure may be applied to mobile devices, tablet PCs,monitors, smartwatches, laptop computers, vehicle displays, etc.Besides, these organic light emitting displays may be applied to vehicledisplays, wearable displays, foldable displays, rollable displays, etc.

Also, organic light emitting displays using the organic light emittingdisplay device according to the second exemplary embodiment of thepresent disclosure may be applied to displays in which the first andsecond light emitting layers emit light of the same color.

Also, organic light emitting displays using the organic light emittingdisplay device according to the third exemplary embodiment of thepresent disclosure may be applied to displays in which at least two ofthe first, second, and third light emitting layers emit light of thesame color.

FIGS. 4 and 5 are energy band diagrams of an organic light emittingdisplay device of the present disclosure. Referring to FIG. 4, the anode110, the hole injection layer 120, the hole transport layer 130, and thelight emitting layer 140 are illustrated. The hole injection layer 120may be formed of a single material comprising a compound of thisdisclosure. The hole transport layer 130 may be formed of, for example,NPD. Since the LUMO energy level of the compound in the hole injectionlayer 120 is similar to or lower than the HOMO energy level of the holetransport layer 130, electrons are accepted from the HOMO energy levelof the hole transport layer 130 to the LUMO energy level of thecompound, thereby forming a hole transport path. Accordingly, holes canbe smoothly injected from the hole injection layer 120 into the holetransport layer 130 through the hole transport path (indicated by thearrows) between the hole injection layer 120 and the hole transportlayer 130.

Referring to FIG. 5, the hole injection layer 120 may comprise a dopantintroduced into a host. Accordingly, a compound of this disclosure actsas the dopant. Since the LUMO energy level of the compound used as adopant for the hole injection layer 120 is similar to or lower than theHOMO energy level of the host, electrons are accepted from the HOMOenergy level of the host to the LUMO energy level of the compound ofthis disclosure, thereby forming a hole transport path (indicated by thearrow). Accordingly, holes can be smoothly injected from the holeinjection layer 120 into the hole transport layer 130 through the holetransport path between the HOMO energy level of the host and the LUMOenergy level of the compound of this disclosure, within the holeinjection layer 120. As a result, the use of the compound of thisdisclosure as a dopant for the hole injection layer 120 facilitates thetransfer of holes from the hole injection layer 120 into the holetransport layer 130, leading to a reduction in operating voltage.

Although FIGS. 4 and 5 are explained with respect to the hole injectionlayer by way of example, the same may apply when the hole injectionlayer 120 is replaced with the P-type charge generation layer 160P ofFIG. 2 and the hole transport layer 130 is replaced with the second holetransport layer 170 of FIG. 2. Accordingly, referring to FIG. 4, if thehole injection layer 120 is replaced with the P-type charge generationlayer 160P of FIG. 2, the P-type charge generation layer 160P may beformed of a single material comprising a compound of this disclosure.Also, referring to FIG. 5, the P-type charge generation layer 160P maycomprise a compound of this disclosure as a dopant.

Moreover, the same applies when the hole injection layer 120 is replacedwith the P-type charge generation layer 160P of FIG. 3 and the holetransport layer 130 is replaced with the second hole transport layer 170of FIG. 3. Accordingly, referring to FIG. 4, if the hole injection layer120 is replaced with the P-type charge generation layer 160P of FIG. 3,the P-type charge generation layer 160P may be formed of a singlematerial comprising a compound of this disclosure. Also, referring toFIG. 5, the P-type charge generation layer 160P may comprise a compoundof this disclosure as a dopant.

Furthermore, the same applies when the hole injection layer 120 isreplaced with the P-type charge generation layer 230P of FIG. 3 and thehole transport layer 130 is replaced with the third hole transport layer240 of FIG. 3. Accordingly, referring to FIG. 4, if the hole injectionlayer 120 is replaced with the P-type charge generation layer 230P ofFIG. 3, the P-type charge generation layer 230P may be formed of asingle material comprising a compound of this disclosure. Also,referring to FIG. 5, the P-type charge generation layer 230P maycomprise a compound of this disclosure as a dopant.

Hereinafter, synthesis examples of compounds of the present disclosurewill be described in detail. However, the following examples are onlyfor illustration, and the present disclosure is not limited thereto.

Synthesis of Compound B31 1) Preparation of1,5-bis(chloromethyl)-2,4-bis(2-phenylethynyl)benzene

2-bromophenyl)acetonitrile (0.12 mol),bis(triphenylphosphine)palladium(II)chloride (PdCl₂(PPh₃)₂) (2 mmol),copper iodide (CuI) (2 mmol), triphenylphosphine (PPh₃) (4 mmol), anddiisopropylamine (i-Pr₂NH) (0.1 mol) were put into a 250 ml two-neckedflask under a nitrogen atmosphere and stirred for 5 min at roomtemperature, and then 1,5-dibromophenyl-2,4-dicarbonitrile (0.05 mol)was added to the mixture and stirred for 24 hours at 50° C. An organiclayer was obtained by extraction with H₂O/ethyl acetate, dried overmagnesium sulfate (MgSO₄), and then subjected to column chromatographyto give 10.9 g of solid (yield: 61%).

2) Preparation of3,5-dihydro-3,5-dioxo-2,6-diphenyl-s-indacene-1,7-dicarbonitrile

1,5-bis(chloromethyl)-2,4-bis(2-phenylethynyl)benzene (0.03 mol),palladium(II) chloride (PdCl₂) (6.1 mmol), silver hexafluoroantimonate(AgSbF₆) (9.1 mmol), and diphenylsulfoxide (Ph₂SO) (0.18 mol) weredissolved in a 250 ml two-necked flask with dichloroethylene (DCE) andstirred for 24 hours at 60° C., and then cesium carbonate (Cs₂CO₃)(0.074 mol) was added to the mixture and stirred for 12 hours. After thereaction, an extract was obtained by extraction with dichloromethane(CH₂Cl₂), which was dried up after the extraction, and then put into 35%hydrochloric acid (HCl) and stirred for 2 hours. An organic layer wasobtained by extraction with a dichloromethane/ammonium chloride(CH₂Cl₂/aq.NH₄Cl) solution, dried over magnesium sulfate (MgSO₄), andthen subjected to column chromatography to give 4.4 g of solid (yield:38%).

3) Preparation of3,5-bis(dicyanomethylene)-3,5-dihydro-2,6-diphenyl-s-indacene-1,7-dicarbonitrile

3,5-dihydro-3,5-dioxo-2,6-diphenyl-s-indacene-1,7-dicarbonitrile (0.01mol), malononitrile (0.062 mol), and dichloromethane (CH₂Cl₂) were putinto a 100 ml two-necked flask and stirred for 30 min under an argonatmosphere. Titanium(IV) chloride (TiCl₄) (0.062 mol) was slowly addedto the mixture, followed by the addition of pyridine (0.1 mol), andstirred at room temperature. An organic layer was obtained by extractionwith a dichloromethane/ammonium chloride (CH₂Cl₂/aq.NH₄Cl) solution,dried over magnesium sulfate (MgSO₄), and then subjected to columnchromatography to give 1.6 g of solid, i.e., Compound B31 (yield: 32%).

Synthesis of Intermediate 1) Preparation of1,5-bis(chloromethyl)-2,4-bis(2-phenylethynyl)benzene

4-ethenylbenzonitrile (0.12 mol),bis(triphenylphosphine)palladium(II)chloride (PdCl₂(PPh₃)₂) (2 mmol),copper iodide (CuI) (2 mmol), triphenylphosphine (PPh₃) (4 mmol), anddiisopropylamine (i-Pr₂NH) (0.1 mol) were put into a 250 ml two-neckedflask under a nitrogen atmosphere and stirred for 5 min at roomtemperature, and then 1,4-dibromo-2,5-di(cyanomethyl)benzene (0.05 mol)was added to the mixture and stirred for 24 hours at 50° C. An organiclayer was obtained by extraction with H₂O/ethyl acetate, dried overmagnesium sulfate (MgSO₄), and then subjected to column chromatographyto give 13.8 g of solid (yield: 68%).

2) Preparation of2,6-bis(4-cyanophenyl)-3,7-dihydro-3,7-dioxo-s-indacene-1,5-dicarbonitrile

1,4-di(cyanomethyl)-2,5-bis(2-(4-cyanophenyl)ethynyl)benzene (0.034mol), palladium(II)chloride (PdCl₂) (6.8 mmol), silverhexafluoroantimonate (AgSbF₆) (10.2 mmol), and diphenylsulfoxide (Ph₂SO)(0.2 mol) were dissolved in a 250 ml two-necked flask withdichloroethylene (DCE) and stirred for 24 hours at 60° C. After thereaction, an extract was obtained by extraction with dichloromethane(CH₂Cl₂), which was dried up after the extraction, and then put into 35%hydrochloric acid (HCl) and stirred for 2 hours. An organic layer wasobtained by extraction with a dichloromethane/ammonium chloride(CH₂Cl₂/aq.NH₄Cl) solution, dried over magnesium sulfate (MgSO₄), andthen subjected to column chromatography to give 5.9 g of solid, i.e., anintermediate, (yield: 48%).

Synthesis of Compound A33

2,6-bis(4-cyanophenyl)-3,7-dihydro-3,7-dioxo-s-indacene-1,5-dicarbonitrile(13.6 mmol), malononitrile (0.082 mol), and dichloromethane (CH₂Cl₂)were put into a 100 ml two-necked flask and stirred for 30 min under anargon atmosphere. Titanium(IV)chloride (TiCl₄) (0.082 mol) was slowlyadded to the mixture, followed by the addition of pyridine (0.1 mol),and stirred at room temperature. After the reaction, an organic layerwas obtained by extraction with a dichloromethane/ammonium chloride(CH₂Cl₂/aq.NH₄Cl) solution, dried over magnesium sulfate (MgSO₄), andthen subjected to column chromatography to give 2.5 g of solid, i.e.,Compound A33 (yield: 35%).

Synthesis of Compound A62

2,6-bis(4-cyanophenyl)-3, 7-dihydro-3,7-dioxo-s-indacene-1,5-dicarbonitrile (0.01 mol),5-(cyanomethyl)benzene-1,3-dinitrile (0.06 mol), and chloromethane(CH₂Cl₂) were put into a 100 ml two-necked flask and stirred for 30 minunder an argon atmosphere. Titanium(IV)chloride (TiCl₄) (0.06 mol) wasslowly added to the mixture, followed by the addition of pyridine (0.1mol), and stirred at room temperature. An organic layer was obtained byextraction with a dichloromethane/ammonium chloride (CH₂Cl₂/aq.NH₄Cl)solution, dried over magnesium sulfate (MgSO₄), and then subjected tocolumn chromatography to give 2.3 g of solid, i.e., Compound A62 (yield:31%).

Synthesis of Compound A63

2,6-bis(4-cyanophenyl)-3,7-dihydro-3,7-dioxo-s-indacene-1,5-dicarbonitrile(0.01 mol), 2-(perfluoropyridin-4-yl)acetonitrile (0.06 mol), andchloromethane (CH₂Cl₂) were put into a 100 ml two-necked flask andstirred for 30 min under an argon atmosphere. Titanium(IV)chloride(TiCl₄) (0.06 mol) was slowly added to the mixture, followed by theaddition of pyridine (0.1 mol), and stirred at room temperature. Afterthe reaction, an organic layer was obtained by extraction with adichloromethane/ammonium chloride (CH₂Cl₂/aq.NH₄Cl) solution, dried overmagnesium sulfate (MgSO₄), and then subjected to column chromatographyto give 2.2 g of solid, i.e., Compound A63 (yield: 28%).

Hereinafter, examples for fabricating an organic light emitting displaydevice of this disclosure will be disclosed. It should be noted thatmaterials of the following hole injection layer and P-type chargegeneration layer do not limit the scope of this disclosure.

Test 1: Monolithic Device Example 1

An organic light emitting display device was fabricated by forming, ananode, a hole injection layer, a hole transport layer, a blue lightemitting layer, an electron transport layer, an electron injectionlayer, and a cathode on a substrate. Here, the hole injection layer wasformed of Compound B31. After the deposition of these layers, the devicewas transferred from the deposition chamber into a dry box forencapsulation, and was subsequently encapsulated using an UV-curableepoxy resin and a moisture getter. The organic light emitting displaydevice thus obtained was connected to an external power supply source,and upon application of direct current voltage, the results in Table 1were obtained. The characteristics of all the fabricated devices wereevaluated using a constant current source (KEITHLEY) and a photometer(PR650) at room temperature.

Example 2

It has the same elements as the above-described Example 1, and the holeinjection layer was formed of NPD doped with 10% Compound B31.

Example 3

It has the same elements as the above-described Example 1, and the holeinjection layer was formed of Compound A33.

Example 4

It has the same elements as the above-described Example 1, and the holeinjection layer was formed of NPD doped with 10% Compound A33.

Example 5

It has the same elements as the above-described Example 1, and the holeinjection layer was formed of Compound A62.

Example 6

It has the same elements as the above-described Example 1, and the holeinjection layer was formed of NPD doped with 10% Compound A62.

Example 7

It has the same elements as the above-described Example 1, and the holeinjection layer was formed of Compound A63.

Example 8

It has the same elements as the above-described Example 1, and the holeinjection layer was formed of NPD doped with 10% Compound A63.

Comparative Example 1

It has the same elements as the above-described Example 1, and the holeinjection layer was formed HAT-CN.

Comparative Example 2

It has the same elements as the above-described Example 2, and the holeinjection layer was formed of NPD doped with 10% HAT-CN.

Comparative Example 3

It has the same elements as the above-described Example 2, but withoutthe hole injection layer.

The operating voltage, efficiency, and external quantum efficiency ofthe devices fabricated according to Examples 1 to 8 of the presentdisclosure and Comparative Examples 1, 2, and 3 set forth above weremeasured and shown in the following Table 1. (The devices were driven ata drive current of 10 mA/cm² to measure the operating voltage,efficiency, and external quantum efficiency).

TABLE 1 Operating Efficiency External quantum voltage (V) (Cd/A)efficiency (%) Example 1 4.2 4.0 4.5 Example 2 4.1 4.4 4.9 Example 3 3.94.5 5.2 Example 4 3.8 4.5 5.2 Example 5 4.0 4.3 5.0 Example 6 4.0 4.45.1 Example 7 4.1 4.2 5.0 Example 8 4.0 4.4 5.0 Comparative Example 14.2 4.1 4.7 Comparative Example 2 6.0 3.0 3.9 Comparative Example 3 6.81.8 2.3

Referring to Table 1, Example 1 in which the hole injection layercomprises Compound B31 of this disclosure and Comparative Example 1 inwhich HAT-CN is used as the hole injection layer showed similar levelsof operating voltage, efficiency, and external quantum efficiency.Example 2 in which a hole injection layer of NPD is doped with CompoundB31 of this disclosure showed a 1.9 V decrease in operating voltage, a1.4 cd/A increase in efficiency, and 1.0% increase in external quantumefficiency, compared to Comparative Example 2 in which a hole injectionlayer of NPD is doped with HAT-CN. Example 1 of this disclosure showed a2.6 V decrease in operating voltage, a 2.2 cd/A increase in efficiency,and 2.2% increase in external quantum efficiency, and Example 2 showed a2.7 V decrease in operating voltage, a 2.6 cd/A increase in efficiency,and a 2.6% increase in external quantum efficiency, compared toComparative Example 3 in which the hole injection layer was not formed.

Also, Example 3 in which the hole injection layer comprises Compound A33of this disclosure showed a 0.3 V decrease in operating voltage, a 0.4cd/A increase in efficiency, and a 0.5% increase in external quantumefficiency, compared to Comparative Example 1 in which HAT-CN is used asthe hole injection layer. Example 4 in which a hole injection layer ofNPD is doped with Compound A33 of this disclosure showed a 2.2 Vdecrease in operating voltage, a 1.5 cd/A increase in efficiency, and1.3% increase in external quantum efficiency, compared to ComparativeExample 2 in which a hole injection layer of NPD is doped with HAT-CN.Example 3 of this disclosure showed a 2.9 V decrease in operatingvoltage, a 2.7 cd/A increase in efficiency, and 2.9% increase inexternal quantum efficiency, and Example 4 showed a 3.0 V decrease inoperating voltage, a 2.7 cd/A increase in efficiency, and a 2.9%increase in external quantum efficiency, compared to Comparative Example3 in which the hole injection layer was not formed.

Also, Example 5 in which the hole injection layer comprises Compound A62of this disclosure showed a 0.2 V decrease in operating voltage, a 0.2cd/A increase in efficiency, and a 0.3% increase in external quantumefficiency, compared to Comparative Example 1 in which HAT-CN is used asthe hole injection layer. Example 6 in which a hole injection layer ofNPD is doped with Compound A62 of this disclosure showed a 2.0 Vdecrease in operating voltage, a 1.4 cd/A increase in efficiency, and1.2% increase in external quantum efficiency, compared to ComparativeExample 2 in which a hole injection layer of NPD is doped with HAT-CN.Example 5 of this disclosure showed a 2.8 V decrease in operatingvoltage, a 2.5 cd/A increase in efficiency, and 2.7% increase inexternal quantum efficiency, and Example 6 showed a 2.8 V decrease inoperating voltage, a 2.6 cd/A increase in efficiency, and a 2.8%increase in external quantum efficiency, compared to Comparative Example3 in which the hole injection layer was not formed.

Also, Example 7 in which the hole injection layer comprises Compound A63of this disclosure showed a 0.1 V decrease in operating voltage, a 0.1cd/A increase in efficiency, and a 0.3% increase in external quantumefficiency, compared to Comparative Example 1 in which HAT-CN is used asthe hole injection layer. Example 8 in which a hole injection layer ofNPD is doped with Compound A63 of this disclosure showed a 2.0 Vdecrease in operating voltage, a 1.4 cd/A increase in efficiency, and1.1% increase in external quantum efficiency, compared to ComparativeExample 2 in which a hole injection layer of NPD is doped with HAT-CN.Example 7 of this disclosure showed a 2.7 V decrease in operatingvoltage, a 2.4 cd/A increase in efficiency, and 2.7% increase inexternal quantum efficiency, and Example 8 showed a 2.8 V decrease inoperating voltage, a 2.6 cd/A increase in efficiency, and a 2.7%increase in external quantum efficiency, compared to Comparative Example3 in which the hole injection layer was not formed

From these results, it can be concluded that the organic light emittingdisplay devices of Examples 1 to 8 in which the hole injection layercomprises a compound of this disclosure achieved a reduction inoperating voltage and improvements in efficiency and external quantumefficiency, compared to the organic light emitting display devices ofComparative Examples 1 to 3 in which the hole injection layer is formedof a well-known material. Also, the hole injection layer may form solelyof a compound of this disclosure, or this compound may be used as adopant.

Test 2: Device with Multiple Light Emitting Parts Example 9

An organic light emitting display device was fabricated by forming, afirst light emitting part comprising a hole injection layer, a firsthole transport layer, a fluorescent blue light emitting layer, and afirst electron transport layer, a charge generation layer comprising anN-type charge generation layer and a P-type charge generation layer, asecond light emitting part comprising a second electron injection layer,a fluorescent blue light emitting layer, a second electron transportlayer, and an electron injection layer, and a cathode on a substrate.Here, the hole injection layer and the P-type charge generation layerwere formed of Compound B31. After the deposition of these layers, thedevice was transferred from the deposition chamber into a dry box forencapsulation, and was subsequently encapsulated using an UV-curableepoxy resin and a moisture getter. The organic light emitting displaydevice thus obtained was connected to an external power supply source,and upon application of direct current voltage, the results in Table 2were obtained. The characteristics of all the fabricated devices wereevaluated using a constant current source (KEITHLEY) and a photometer(PR650) at room temperature. Here, the light emitting layers in thefirst and second light emitting parts are blue light emitting layers,but is not limited thereto.

Example 10

It has the same elements as the above-described Example 9, and the holeinjection layer and the P-type charge generation layer were formed ofNPD doped with 10% Compound B31.

Example 11

It has the same elements as the above-described Example 9, and the holeinjection layer and the P-type charge generation layer were formed ofCompound A33.

Example 12

It has the same elements as the above-described Example 9, and the holeinjection layer and the P-type charge generation layer were formed ofNPD doped with 10% Compound A33.

Example 13

It has the same elements as the above-described Example 9, and the holeinjection layer and the P-type charge generation layer were formed ofCompound A62.

Example 14

It has the same elements as the above-described Example 9, and the holeinjection layer and the P-type charge generation layer were formed ofNPD doped with 10% Compound A62.

Example 15

It has the same elements as the above-described Example 9, and the holeinjection layer and the P-type charge generation layer were formed ofCompound A63.

Example 16

It has the same elements as the above-described Example 9, and the holeinjection layer and the P-type charge generation layer were formed ofNPD doped with 10% Compound A63.

Comparative Example 4

It has the same elements as the above-described Example 9, and the holeinjection layer and the P-type charge generation layer were formed ofHAT-CN.

Comparative Example 5

It has the same elements as the above-described Example 9, and the holeinjection layer and the P-type charge generation layer were formed ofNPD doped with 10% HAT-CN.

Comparative Example 6

It has the same elements as the above-described Example 9, but withoutthe hole injection layer and the P-type charge generation layer.

The operating voltage, efficiency, and external quantum efficiency ofthe devices fabricated according to Examples 9 to 16 of the presentdisclosure and Comparative Examples 4, 5, and 6 set forth above weremeasured and shown in the following Table 2. (The devices were driven ata drive current of 10 mA/cm′ to measure the operating voltage,efficiency, and external quantum efficiency).

TABLE 2 Operating Efficiency External quantum voltage (V) (Cd/A)efficiency (%) Example 9 9.2 5.3 6.4 Example 10 8.6 6.5 7.5 Example 118.2 7.2 8.3 Example 12 8.1 7.2 8.3 Example 13 8.4 6.7 7.8 Example 14 8.56.7 7.7 Example 15 8.5 6.7 7.7 Example 16 8.4 6.8 7.8 ComparativeExample 4 9.1 5.4 6.6 Comparative Example 5 13.5 4.5 5.1 ComparativeExample 6 — — —

Referring to Table 2, Example 9 in which the hole injection layer andthe P-type charge generation layer comprise Compound B31 of thisdisclosure and Comparative Example 4 in which HAT-CN is used as the holeinjection layer and the P-type charge generation layer showed similarlevels of operating voltage, efficiency, and external quantumefficiency. Example 10 in which a hole injection layer and P-type chargegeneration layer of NPD are doped with Compound B31 of this disclosureshowed a 4.9 V decrease in operating voltage, a 2.0 cd/A increase inefficiency, and 2.4% increase in external quantum efficiency, comparedto Comparative Example 5 in which a hole injection layer and P-typecharge generation layer of NPD are doped with HAT-CN.

Also, Example 11 in which the hole injection layer and the P-type chargegeneration layer comprise Compound A33 of this disclosure showed a 0.9 Vdecrease in operating voltage, a 1.8 cd/A increase in efficiency, and a1.7% increase in external quantum efficiency, compared to ComparativeExample 4 in which HAT-CN is used as the hole injection layer and theP-type charge generation layer. Example 12 in which a hole injectionlayer and P-type charge generation layer of NPD are doped with CompoundA33 of this disclosure showed a 5.4 V decrease in operating voltage, a2.7 cd/A increase in efficiency, and 3.2% increase in external quantumefficiency, compared to Comparative Example 5 in which a hole injectionlayer and P-type charge generation layer of NPD are doped with HAT-CN.

Also, Example 13 in which the hole injection layer and the P-type chargegeneration layer comprise Compound A62 of this disclosure showed a 0.7 Vdecrease in operating voltage, a 1.3 cd/A increase in efficiency, and a1.2% increase in external quantum efficiency, compared to ComparativeExample 4 in which HAT-CN is used as the hole injection layer and theP-type charge generation layer. Example 14 in which a hole injectionlayer and P-type charge generation layer of NPD are doped with CompoundA62 of this disclosure showed a 5.0 V decrease in operating voltage, a2.2 cd/A increase in efficiency, and 2.6% increase in external quantumefficiency, compared to Comparative Example 5 in which a hole injectionlayer and P-type charge generation layer of NPD are doped with HAT-CN.

Also, Example 15 in which the hole injection layer and the P-type chargegeneration layer comprise Compound A63 of this disclosure showed a 0.6 Vdecrease in operating voltage, a 1.3 cd/A increase in efficiency, and a1.1% increase in external quantum efficiency, compared to ComparativeExample 4 in which HAT-CN is used as the hole injection layer and theP-type charge generation layer. Example 16 in which a hole injectionlayer and P-type charge generation layer of NPD are doped with CompoundA63 of this disclosure showed a 5.1 V decrease in operating voltage, a2.3 cd/A increase in efficiency, and 2.7% increase in external quantumefficiency, compared to Comparative Example 5 in which a hole injectionlayer and P-type charge generation layer of NPD are doped with HAT-CN.

In Comparative Example 6 in which the hole injection layer was notformed, the device could not be driven.

Also, at least one among the hole injection layer and the P-type chargegeneration layer may form solely of a compound of this disclosure, orthis compound may be used as a dopant.

For reference, the energy levels of the well-known compounds and thecompounds used in the examples of the present disclosure are shown inthe following Table 3. The energy levels are calculated by DFT (DensityFunctional Theory) simulation. The DFT is one of the electronicstructure computational methods. The function (basis set) used in thesimulation is B3LYP/6-31G*, but is not limited thereto.

TABLE 3 HOMO (eV) LUMO (eV) NPD −5.45 −2.30 HAT-CN −9.55 −6.07 F₄-TCNQ−8.33 −5.78 B31 −7.9 −5.72

Referring to Table 3, it can be found out that a compound of thisdisclosure showed a LUMO energy level closer to −5.45 eV, which is theHOMO energy level of NPD used as a host for the hole injection layer orP-type charge generation layer, compared to HAT-CN and F₄-TCNQ, known asp-type dopant materials. As such, the LUMO energy level of the compoundof this disclosure is similar to or lower than the HOMO energy level ofthe host for the hole injection layer or P-type charge generation layer,which may lead to an improvement in the hole injection properties.

From these results, it can be concluded that the organic light emittingdisplay device of Example 9 in which the hole injection layer and theP-type charge generation layer comprise a compound of this disclosureachieved almost the same levels of operating voltage, efficiency, andexternal quantum efficiency as the organic light emitting display deviceof Comparative Example 4. Also, it can be concluded that the organiclight emitting display device of Example 10 in which the hole injectionlayer and the P-type charge generation layer comprise a compound of thisdisclosure achieved a 4.9 V decrease in operating voltage, a 2.0 cd/Aincrease in efficiency, and a 2.4% increase in external quantumefficiency, compared to the organic light emitting display device ofComparative Example 5.

As discussed above, a compound of this disclosure comprises indene as acore, which provides process stability against heat or deposition, thussimplifying the composition and deposition of the compound. Moreover,the compound of this disclosure can improve the hole injectionproperties by comprising an electron-attracting substituent attached tothe core and making the LUMO energy level of the compound similar to orlower than the HOMO energy level of host of the hole injection layer,the host of the P-type charge generation layer, or the hole transportlayer.

Accordingly, at least one among the hole injection layer and the P-typecharge generation layer is formed of the compound of this disclosure toensure the process stability of the compound, which simplifies thefabrication of the organic light emitting display device. Moreover, thecompound of this disclosure can reduce the device's operating voltageand improve its efficiency and lifetime since the improvement in holeinjection properties helps to facilitate the transfer of holes from theanode to the light emitting layer.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the organic light emittingdisplay device of the present disclosure without departing from thespirit or scope of the disclosure. Thus, it is intended that the presentdisclosure cover the modifications and variations of this disclosureprovided they come within the scope of the appended claims and theirequivalents.

What is claimed is:
 1. An organic light emitting display device,comprising: at least one light emitting part between an anode and acathode, the at least one light emitting part having at least oneorganic layer and a light emitting layer, wherein the at least oneorganic layer comprises a compound represented by the following ChemicalFormula 1 or 2:

where R₁ to R₆ each independently represents one among a hydrogen atom,a substituted or unsubstituted aryl group with 6 to 12 carbon atoms, asubstituted or unsubstituted heteroaryl group with 1 to 12 carbon atomsand 1 to 4 heteroatoms one among O, N, S, and Si, a substituted orunsubstituted alkyl group with 1 to 12 carbon atoms, a substituted orunsubstituted alkoxy group with 1 to 12 carbon atoms, a substituted orunsubstituted ether group with 1 to 12 carbon atoms, a cyano group, afluorine group, a trifluoromethyl group, a trifluoromethoxy group, and atrimethylsilyl group, and at least one among R₁ to R₆ comprises a cyanogroup, and Z₁ and Z₂ are independently represented by the followingChemical Formula 3:

where A and B independently represent one among a hydrogen atom, asubstituted or unsubstituted aryl group with 6 to 12 carbon atoms, asubstituted or unsubstituted heteroaryl group with 1 to 12 carbon atomsand 1 to 4 heteroatoms one among O, N, S, and Si, a substituted orunsubstituted alkyl group with 1 to 12 carbon atoms, a substituted orunsubstituted alkoxy group with 1 to 12 carbon atoms, a substituted orunsubstituted ether group with 1 to 12 carbon atoms, a cyano group, afluorine group, a trifluoromethyl group, a trifluoromethoxy group, and atrimethylsilyl group.
 2. The organic light emitting display device ofclaim 1, wherein the substituent of the aryl group, heteroaryl group,alkyl group, alkoxy group, and ether group is one among an alkyl with 1to 12 carbon atoms, an aryl with 6 to 15 carbon atoms, a hetero alkylwith 1 to 15 carbon atoms and 1 to 4 heteroatoms one among O, N, S, andSi, a cyano group, a fluorine group, a trifluoromethyl group, atrifluoromethoxy group, and a trimethylsilyl group.
 3. The organic lightemitting display device of claim 1, wherein the compound represented byChemical Formula 1 includes one among the following compounds:


4. The organic light emitting display device of claim 1, wherein thecompound represented by the above Chemical Formula 2 is one among thefollowing compounds:


5. The organic light emitting display device of claim 1, wherein the atleast one organic layer includes a hole injection layer.
 6. The organiclight emitting display device of claim 5, wherein a dopant of the holeinjection layer includes the compound.
 7. The organic light emittingdisplay device of claim 5, wherein the hole injection layer includes thecompound.
 8. The organic light emitting display device of claim 1,wherein the at least one organic layer includes a P-type chargegeneration layer.
 9. The organic light emitting display device of claim8, wherein a dopant of the P-type charge generation layer includes thecompound.
 10. The organic light emitting display device of claim 8,wherein the P-type charge generation layer includes the compound.
 11. Anorganic light emitting display device, comprising: at least one lightemitting part between an anode and a cathode, the at least one lightemitting part having a hole injection layer and a light emitting layer;and a charge generation layer having a P-type charge generation layerbetween the at least one light emitting part, wherein at least one amongthe hole injection layer and the P-type charge generation layercomprises a compound represented by the following Chemical Formula 1 or2:

where R₁ to R₆ each independently represents one among a hydrogen atom,a substituted or unsubstituted aryl group with 6 to 12 carbon atoms, asubstituted or unsubstituted heteroaryl group with 1 to 12 carbon atomsand 1 to 4 heteroatoms one among O, N, S, and Si, a substituted orunsubstituted alkyl group with 1 to 12 carbon atoms, a substituted orunsubstituted alkoxy group with 1 to 12 carbon atoms, a substituted orunsubstituted ether group with 1 to 12 carbon atoms, a cyano group, afluorine group, a trifluoromethyl group, a trifluoromethoxy group, and atrimethylsilyl group, and at least one among R₁ to R₆ comprises a cyanogroup, and Z₁ and Z₂ are independently represented by the followingChemical Formula 3:

where A and B independently represent one among a hydrogen atom, asubstituted or unsubstituted aryl group with 6 to 12 carbon atoms, asubstituted or unsubstituted heteroaryl group with 1 to 12 carbon atomsand 1 to 4 heteroatoms one among O, N, S, and Si, a substituted orunsubstituted alkyl group with 1 to 12 carbon atoms, a substituted orunsubstituted alkoxy group with 1 to 12 carbon atoms, a substituted orunsubstituted ether group with 1 to 12 carbon atoms, a cyano group, afluorine group, a trifluoromethyl group, a trifluoromethoxy group, and atrimethylsilyl group.
 12. The organic light emitting display device ofclaim 11, wherein the substituent of the aryl group, heteroaryl group,alkyl group, alkoxy group, and ether group is one among an alkyl with 1to 12 carbon atoms, an aryl with 6 to 15 carbon atoms, a hetero alkylwith 1 to 15 carbon atoms and 1 to 4 heteroatoms one among O, N, S, andSi, a cyano group, a fluorine group, a trifluoromethyl group, atrifluoromethoxy group, and a trimethylsilyl group.
 13. The organiclight emitting display device of claim 11, wherein the compoundrepresented by Chemical Formula 1 includes one among the followingcompounds:


14. The organic light emitting display device of claim 11, wherein thecompound represented by the above Chemical Formula 2 is one among thefollowing compounds:


15. The organic light emitting display device of claim 11, wherein adopant of the hole injection layer includes the compound.
 16. Theorganic light emitting display device of claim 11, wherein the holeinjection layer includes the compound.
 17. The organic light emittingdisplay device of claim 11, wherein a dopant of the P-type chargegeneration layer includes the compound.
 18. The organic light emittingdisplay device of claim 11, wherein the P-type charge generation layerincludes the compound.